Found this on the internet
Why do companies offer free solar panels?
Installation costs (including the cost of the panels themselves) range from £6,000 to over £10,000. If a company offers to install these pricey panels for free, you’d be forgiven for thinking ‘yes please’.
But these companies aren’t doing this out of the kindness of their hearts: although you’ll save some money with the electricity you use, it is the company that actually owns the panels, so it gets to keep all the income created by the FIT scheme, not you.
http://www.moneywise.co.uk/home-mortgage/improvements/six-things-to-consider-buying-solar-panels